The switch comprises a stator which is rigidly secured to a lock cylinder case and a rotor which is rigidly fixed to a lock cylinder. The rotor rotates within the stator which has two concentric and partially overlapping circular arc conductors. The rotor drives an elliptical slip ring in a groove between the conductors and between one of the conductors and a slide surface where the conductors do not overlap. The frictional connection between the conductors and the slip ring holds the slip ring from being fully drawn out of contact with both conductors when the locking cyclinder is turned from closed to neutral position and holds the slip ring from being drawn into contact with both conductors when the locking cylinder is turned from open to neutral position.